My V8 E30s Battery wont hold charge?? Its new...

[drifty340i]

Hi guys im having a bit of an issue with my e30 v8, the battery wont hold its charge for longer than a week,

now the alternator is working fine as ive just had that tested, also the battery is fine as thats brand new and its a 660cca and its been tested as well.

An auto electrical guy has suggested it might well be a draining power somewhere
Where are the usual power leaks in e30s?

Any help would be great

Riley

[dsobering47]

1) make sure the car is off.

2) wait 5 minutes

3) goto your battery and measure the amperage, i believe, across it. (from B+ to b-)

4) start pulling fuses one by one until the amperage drops significantly

5) trace the circuit on the last fuse you pulled (say the radio) and check all connections or that area to see what is staying on.

[VacMan]

Aftermarket stereo or other non-BMW wiring? That's about 80% likely to be your culprit.

[nando]

grounds, grounds grounds-- make sure you have good grounds to the engine, alt and battery.

[m42technic]

3) goto your battery and measure the amperage, i believe, across it. (from B+ to b-)

You cant measure amperage in parallel with the battery, you need to measure in series with one of the battery cables.

[drifty340i]

Sweet ill check those out tonight and get back you you all

[thectrlguy]

Bingo +1

You cant measure amperage in parallel with the battery, you need to measure in series with one of the battery cables.

[express_wagon]

check your hazard switch

[gearheadE30]

Common places in the normal e30 are worn door and trunk light switches, head units, and bad grounds. Because of your engine swap, it could be a wide variety of stuff, so the pulling fuses method is probably your best bet.

[Julien]

i say engine ground

[Pettas]

Had same issue on a stock eta with high milage. I took all the terminals apart(engine bay power) etc... and gave them a good cleaning and hooked it back up. Fixed my issue. Cleaned the ground and power cable on the battery as well.

[drifty340i]

Cheers will look into those as well

[japspecvr6]

I think im Having a Grounds problem as well. My lights flicker a little and i have a swap. How can i fix this ?

[drifty340i]

Ive still got to fix mine

[Madhatter]

easiest way in the past for me to find culprits like this is with a test light and just run through all the fuses and relays to see what has power when it shouldnt. Saves pulling and/or measuring stuff.